The present application claims priority under 35 U.S.C. xc2xa7119 to Japanese Patent Application No. 2000-017044, filed Jan. 26, 2000, entitled xe2x80x9cAlternating-current Electric Power Controlling Method And Apparatus.xe2x80x9d The contents of that application are incorporated herein by reference in their entirety.
1. Field of the Invention
The present invention relates to an alternating-current electric power controlling apparatus and a method for controlling supply of alternating-current electric power to an electric load.
2. Description of the Background
Conventionally, in order to control a supply of electric power from an alternating-current electric power source to an electric load, phase control or on/off control have been utilized. Referring to FIG. 21A, in the phase control, switching is carried out within each half cycle of alternating-current wave at a variable phase angle. The hatching portions of the electric power wave are supplied to the electric load. In the phase control, the phase angle is controlled to control the electric power to be supplied to the electric load. Referring to FIG. 21B, in the on/off control, the electric power is supplied to the electric load during a variable period of time.
In the phase control and the on/off control, however, the possibility of occurrence of harmonic current and flicker increases because current is, always in the phase control and sometimes in the on/off control, abruptly shut off. Therefore, it has been difficult to satisfy the standard requirements of IEC 6100-3-2 and IEC 6100-3-3 which the International Electric Standard Organization adopted.
According to one aspect of the invention, an alternating-current electric power controlling apparatus includes a switch and a controller. The switch is configured to be turned on or off to connect or disconnect an alternating-current electric power source and an electric load. The controller is configured to control the switch to turn on or off to adjust supply of electric power from the alternating-current electric power source to the electric load. The switch is configured to be turned on or off when an electric power amplitude is substantially equal to 0.
According to another aspect of the invention, an electric appliance includes an electric load, a switch and a controller. The switch is configured to be turned on or off to connect or disconnect an alternating-current electric power source and the electric load. The controller is configured to control the switch to turn on or off to adjust supply of electric power from the alternating-current electric power source to the electric load. The switch is configured to be turned on or off when an electric power amplitude is substantially equal to 0.
According to yet another aspect of the invention, an alternating-current electric power controller includes a controlling unit which is configured to control a switch to turn on or off to adjust supply of electric power from an alternating-current electric power source to an electric load. The switch is configured to be turned on or off when an electric power amplitude is substantially equal to 0.
According to a further aspect of the invention, an alternating-current electric power supplying system includes an alternating-current electric power source, a switch and a controller. The switch is configured to be turned on or off to connect or disconnect the alternating-current electric power source and the electric load. The controller is configured to control the switch to turn on or off to adjust supply of electric power from the alternating-current electric power source to the electric load. The switch is configured to be turned on or off when an electric power amplitude is substantially equal to 0.
According to yet another aspect of the invention, a method for controlling supply of alternating-current electric power to an electric load, includes controlling a switch to turn on or off to adjust the supply of electric power from an alternating-current electric power source to the electric load such that the switch is turned on or off when an electric power amplitude is substantially equal to 0.
According to yet another aspect of the invention, an alternating-current electric power controlling apparatus includes a switch and a controller. The switch unit is configured to be turned on or off to connect or disconnect an alternating-current electric power source and the electric load and is configured to detect that an electric power amplitude is substantially equal to 0. The controller is configured to control the switch unit to turn on or off to adjust supply of the electric power from the alternating-current electric power source to the electric load. The switch unit is configured to be turned on or off when the electric power amplitude is substantially equal to 0 and when the controller outputs control signal to the switch unit to turn on or off the switch unit.
According to further aspect of the invention, an alternating-current electric power controlling apparatus includes a switch, a timing unit and a controller. The switch is configured to be turned on or off to connect or disconnect an alternating-current electric power source and an electric load. The timing unit is configured to determine that an electric power amplitude is substantially equal to 0. The controller is configured to control the switch to turn on or off to adjust supply of electric power from the alternating-current electric power source to the electric load. The switch is configured to be turned on or off when the a timing unit determines that an electric power amplitude is substantially equal to 0.
According to yet further aspect of the invention, an alternating-current electric power controlling apparatus includes a switch and a controller. The switch is configured to be turned on or off to connect or disconnect an alternating-current electric power source and an electric load. The controller is configured to control the switch to turn on or off to adjust supply of electric power from the alternating-current electric power source to the electric load. The switch is configured to be turned on or off when a phase angle xcex8 of a wave of the electric power is in a range of approximately 0xc2x0xc2x120xc2x0.